The effects of artificial aging on high translucent zirconia

Abstract

Zirconia is known for its high strength but lacking translucency. Recently, a new type of high translucent zirconia, 5 mol% yttria partially stabilized zirconia (5Y-PSZ), with a larger fraction of cubic zirconia phase has become commercially available. However, the resistance to aging of these commercially available zirconia materials is not yet fully established.

Purpose: The aim of the present study was to analyze the effects of artificial aging on surface roughness, transparency, phase transformation and biaxial flexural strength of two 5Y-PSZ products, DD cubeX² and Prettau Anterior.

Materials and methods: The artificial aging was performed in an autoclave under 2 bars of pressure at 134 °C for 10 hours, which is estimated to correspond to 30–40 years in vivo. Artificial aging for 10 hours had no significant effect on surface roughness, transparency, or phase transformation for either of the tested materials.

Results: DD cubeX² had higher mean flexural strength than Prettau Anterior both before and after artificial aging for 10 hours (p < .05). DD cubeX² showed, however, a significant reduction in flexural strength after artificial aging (p < .05), whereas Prettau Anterior showed a slight increase in flexural strength after artificial aging but not at a significant level.

Conclusion: Within the limitation of the present study, both DD cubeX² and Prettau Anterior seems to be relatively resistant to aging. However, a wider range of measured flexural strength indicated that Prettau Anterior probably is a less stable material than DD cubeX², which also means that the flexural strength of DD cubeX² could be more predictable.

Keywords:

• High translucent zirconia
• 5Y-PSZ
• aging
• biaxial flexural strength
• transparency
• surface roughness

Acknowledgements

The authors would also like to thank Dr Shi Tang at the Organic Photonics & Electronics Group, Department of Physics, Umeå University for performing the visible transmittance analysis. Thanks to Research engineer Helena Königsson at the Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, for providing the autoclave used in this study. In addition, thanks to professor emeritus Göran Sjögren and dental technician instructor Ylva Burström at Department of Odontology, Dental Materials Science, Umeå University, for consulting and for providing materials. We would also like to thank senior research engineer Anders Esberg at Department of Odontology, Cariology, Umeå University for advice regarding the statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.